Temperature-equalizing coil



T. L. HARTMAN. nuria/Huma EQuAuzlNG con.

APPLICATIUN FILED NOV- 2.1917.

Patented Feb. 17,1920.

"gl, Flagg ff w@ of the return bend THOMAS L. HARTMAN, OIE PITTSBURGH, PENNSYLVANIA.

TEMPERATRE-EQUALIZIN G COIL.

Specification of Letters Patent.

Patented Feb.r17, 1920.

Appiication sied November 2, i917. serii No. 199,847.

To all whom, it may concern.' y

i Be it known that I, THOMAS L. HARTMAN, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and `State of Pennsylvania., have invented certain new and usefulY Improvements in T empei'ature-Equalizing Coils, of which the following is a specication. v

My invention relates to the art of making temperature equalizing coils of the class used in refrigerating ,apparatus and for heatingor cooiing purposes generally. The inif'ention consists in the method of asseinbling the inner and outer circulating pipes with an intervening concentric space, providing means for bending the said pipes t0- gether while maintaining their operative relatioiis, and in the resulting Vproduct of such operation, having the several features of novelty and advantage hereinafter set forth.

In the drawings illustrating certain preferred forms of the apparatus, and its manner of manufacture ligure 1- is a view in elevation of series of continuous return bend sections, in operative position.

Fig. 2 is an enlarged sectional detail View of an inner and outer pipe section, partly broken away, prepared for bending. K

F ig. 8 is a detail view, partly iii section, portion of' the compound pipe.

F ig. I is a similar view showing the pipes provided with a nipple connection. t

Fig. 5 is an enlarged sectional detail view showing the manner of applying the nipple.

Fig.k 6 is a sectional detail view illustrating the manner of'welding the ends 0f the outer pipes 'together and of providing the spacing connection for the inner pipe.

Fig. 7 is a cross section on the line VII, VII, of Fig. 6. v

F ig. 8 is a detail sectional view of the ends of the outer pipe prior to welding,

Fig. 9 is a similar View of the inner ends.

In carrying out my invention the inner pipe 2 is arranged within the outer pipe 3, while straight, and inpsuitable lengths to provide the finished length desired, with an intervening concentric space 4. The inner pipe projects beyond eachv end of the outer pipe as shown and is held in fixed relation thereto by a packing or ring 5 of waste or other suitable substance.

Pire

The space t isfilled with sand or other suitable material, which is tamped or packed compa-ctly by a pneumatic hammer or otherwise so as to provide a comparatively tight resisting body, adapted to resist the pressure ofthe outer pipe in bending and to maintain the pipes in true concentric relation at all times during the bending o-peration.

The pipes as thus assembled are heated at those portions where they are to be bent and are then bent around a former or mandrel by suitable means, providing the loop ends 6, Fig. l, and when this operation is completed, the sand is removed by air pressure or otherwise.

At one stage in the operation, before bending, I provide interior bracing and supporting loop rings 7 which are welded to the outer pipe 3 through suitable openings therein. This may be conveniently done by inserting the thin connecting tongue or band 8 forming the ring between the adjacent ends of outer pipe sections 3, 3, or in suitable clearance notches therein, before these ends are welded together, thereby holding the inner pipe in fixed relation to the outer pipe. In such welding comiection, the outer pipe ends are iiiteriorly scarfed as at 9 so that when the ends are heated and brought together under pressure, they will be oined with substantially Hush interior surfaces and any surplus metal will extend outwardly in the form of an annular ridge l0.

The inner pipe ends are similarly joined by welding but with male and female scarfed terminals l1, l2, which will interlit and prov ile smooth surfaces bot-li inside and outsi e.

At other points than at the welded oints, the band rings 7 are introduced through a suiiiciently large opening in the outer pipe 3 by one end which is passed around the inner pipe 2 and is then again passed or fished through the outer pipe. The ends are brought together, with just sufficient gripping tension to hold the inner pipe centrally of the outer, and the free ends are then welded t-o the outer pipe and the hole vis closed, as indicated at a Fig. 2.

This operation. is yperformed while the pipes are straight, before bending, care being taken to locate the rings at proper distances apart to uniformly hold the inner lpipe in position throughout the length of the entire series of return bend sections.

Also, the attachments should beinade at the side of the outer` pipe 3 which is to be its upper-side when the pipesgare finally arranged in position, as in Fig. 1, which would be alternating positions at the bending locations, so as to always support the inner pipe from the upper wall `of the outer pipe, and

` prevent it from sagging. By this means I insure the continued concentric relations of the pipes and free circulation space between Y drea- At any suitable point or points in the rounded or return bend portions 6 of the pipe'l provide one or more cleaning nipples 13 for each bend extending inwardlythrough the outer and inner lpipe and welded to each, asshown. In this feature, cut through both pipes, as by the yoxyacetylene name, leaving a'soinewhat enlarged hole 14 in the outer pipe, vand am thus able to insert the nipple and to weld it to theinner pipe from the outside. Afterward the enlarged hole is filled, the joint is finished, and the projecting threaded end .of the nipple is covered by a cap 15. Y

At each end the outer pipe 2 isvthen provided with a lateral connection 16., 17, for gas connection and liquor connections, respectively, and the ends 18 of the inner pipe are threaded for connection with the water circulation pipes.-

The series of pipe lengths are mounted in position by a holding rack or frame 19 of suitable construction, and it will bejunderstood that any desirednuinb'er of series may be used, or that the length and capacity of the pipe may be varied as desired'to suit the expected capacity or other requirements.

The advantages of the invention will be readily understood and appreciated by all` those familiar with this class of apparatus. Because of the inner pipe being completely inclosed within the outer pipe throughout its entire length l avoid any exposure at the bends, thereby greatly increasing condensing efficiency, under all conditions and independently of local conditions as to temperature. All leaky joints are eliminated dueto the absence of threaded or packed vconnections, by usingV the electrical welding process, and it is comparatively 'easy to test the pipe with regard to its fluid-'tight condition by compressed air or water. Because of the bends 6 being practically half circular and of uniform maximum diameter, friction 'of' the traversing fluids is reduced to a miniv muni, greatly adding to the efciency of refrigerating or similar apparatus. Y

lThe advantages due tothe novel method of bending greatly contribute to the symmetrical and Vfixedrelations of the inner and outer pipes, assisted by the supporting rings 7,v and there is always an even regular distribution of ammonia around the water pipe.

1. A'teinperature equalizing coil consisting of continuous inner and outerfconcentrically 'spaced pipes bent to provide a concentric wall return bent at intervals`,`and provided with spaced individual holding rings embracing the inner pipe with clearance for circulation and having an attaching terminal extending through and in fixed connection with the outer-pipe.

Y 2. A ktenfiperature equalizing'coil consisting ofcontinuous inner and outer concentrically spaced pipes bent to provide a return bend at intervals, the inner pipe having a series V,of tightly embracing holding rings eachhaving a laterally projecting `portion extending rthrouglfi and iixedly connected Vwith the outer pipe whereby to hold the Vinner and outer pipes in fixed concentric relation with an'intervening annular circulation space therebetween. Y Y

3. A temperature equal'zing coil consisting of a continuous inner and outerconcentrically spaced pipe bent to provide a return bend, and having a nipple extending into the interiorv and welded to each pipe.

4.a temperature equalizing coil Vconsisting of continuous inner Yand outer concentrically kspaced coinpoimd'pipes Ycomposed of annularly scarfed electrically wielded Vsections, the inner andouter sectionsbeing uniformly spaced apart providing a concentric circulationopening throughout the entire coil, and provided at intervals with a ring surrounding the inner .pipe andhaving a terminalextending through and'secured to the outer pipef Y Y j A5. A temperature equalizing coil consisting of a continuous inner and outer concentrically spaced lcompound pipe 'composed of electrically welded sections, the inner and outer sections being spaced apart providing .al concentric circulation opening and provided with concentric wall return bend loops at intervals, and havingisolated-connecting devices secured around the inner pipe and through the wall of the outer pipe.-

In testimony whereof I hereunto affix my signature.

rri-ioMas L. HARTMAN. 

